Inflatable shoe for aircraft



pml 1, m47. W, H. HUNTER 2,418,262

INFLATABLE SHOE FOR AlRCRAFT Filed Sept. 10, 1943 ,/5

Patented Apr. l, 1947 INFLATABLE SHUE FOB, AIRCRAFT Willson H. Hunter, Akron, Ohio, assignor to The E. F. Goodrich Company, New York, N. Y., a corporation of New York Application September 10, 1943, Serial No. 501,783

7 Claims.

formation or cap along the immediate leading edge and in unbalancing and moving the broken pieces of ice for elective removal by the airiiow.

Objects of the invention are to provide for effectively preventing the accumulation of ice on bodies having thin-section leading edges; to provide for elective breaking of ice caps at the leading edge While providing for moving broken ice laterally away from the leading edge for most effective removal in the air flow; to provide for relatively high stretchability immediately at the leading edge While providing restraint of stretchability immediately to the sides thereof and While providing for effective movement of the side portions to remove ice, and to provide simplicity of construction, eiectiveness of operation and convenience of manufacture.

These and other objects and advantages of the invention will be apparent from the following description.

In the accompanying drawings which form a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 vis a perspective view in section of an inflatable shoe mounted on an airfoil having a thin-section leading edge, and constructed in accordance with and embodying the invention, parts being broken away,

Fig. 2. is a view like Fig. 1 but showing the shoe in an inflated condition,

Fig. 3 is a plan View from the top of the shoe, and

Fig. 4 is a sectional view of the attachment of the margin of the shoe to the airioil, parts beingbroken away.-

In the arrangement shown in Fig. 1 an inflatable shoe IIJ including elastic material such as resilient rubber or other rubber-like material, is mounted on an airfoil II such, for example, as

an airplane wing, having a thin-section leading edge I 2.

The shoe Ill comprises a tube portion I3 eX- tending longitudinally along the leading edge I2 and stretchable portions I4 and i5 extending from the sides of the tube portion I3 to the respective margins I6 and II of the shoe, which margins are attached to the airfoil II in a manner to provide for maintaining the shoe in -a condition of` tension therebetween for preventing undue bulging and wrinkling of the exposed surface of the shoe. As shown especially in Fig. 4, each of the margins I6 andI'I are provided with a fabric strip I8 united to the rubber thereof and folded to accommodate a metallic strip element i9 extending throughout the margin, the strip element I9 being desirably in the form of a flat or oval wire.

For attaching the shoe I0 to the airfoil II screws 29 are disposed through the shoe structure just inside the wire I9 and are tapped into hollow threaded rivets 2l set into the metal surface or other structure of the airfoil. The arrangement is such that the wire I9 is adapted to bear against the screws Z0 to maintain the shoe in a condition of tension between its upper and lower margins IIS and I'I. The margins are desirably tapered in section at the portions Ia and Ila extending beyond the wires I 9 to provide fairing for a smooth airflow across the airfoil, and these tapered portions may be provided with a cover strip Ib of rubber and are preferably adhered to the surface of the airfoil by a suitable adhesive such, lfor example, as rubber cement. However, the tube portion I3 and the stretchable portions I and I5 are not adhered to the airfoil Il, so as to permit relative movement therebetween during inl-:lation of the tube I3i.

The tube portion I3 at the leading edge I2 includes an inner wall 22 and an outer wall 23 of suitable elastic material such as resilient rubber-like material and a reinforcing fabric element 224 disposed in the inner wall 22 and in longitudinally extending side regions 25 and 26 of the outer wall 23. In the outer wall 23 the margins of the fabric are spaced apart at El and 32 for providing an intermediate regionV 21 of the outer wall 23 at the leading edge I2 having relatively ,high stretchability by virtue of the elasticity of the material thereof. At the same time, the fabric provides for restraining the stretching of the elastic material immediately to the sides atthe regions 25 and 25 of the tube portion I3 in addition to restraining the stretching of the inner wall 22 thereof. A .suitable conduit 28 of flexible material is attached to the shoe I Il in communication with the inflatable space of the tube portion I3 for admitting air under pressure intermittently to such space. The rubber and fabric parts of the inflatable shoe are united by vulcanization and pressure under heat.

In the operation of the inflatable shoe I Il under ice-forming conditions, air under pressure from a suitable source, which source may be disposed in the fuselage of the aircraft, for example, is admitted cyclically to the tube portion I3 through the interconnecting conduit 28 for expanding and contracting alternately the tube space. During a single cycle, for example, of inflating and deflating the tube portion I3, the tube assumes progressively several different forms such as the forms 29 and 30 shown by the broken lines in Fig. 1, while the stretchable portions III and I stretch progressively to a greater extent than that of the deflated Acondition and move relative to the airfoil II substantially throughout their extent. When the tube is fully inflated, the shoe I0 assumes substantially the position shown especially in Fig. 2.

The longitudinally extending side regions 25 and 26 and the inner wall 22 of the tube portion I3 being substantially restrained against stretching by the reinforcing fabric element 24, the sides of the tube portion bulge outwardly from the airfoil I I assuming a condition of greater bulging or curvature with each increment of inflation which provides a rolling action of the sides of the tube portion I3 away from the airfoil II -and progressivelyelongates chordwise the stretchable portions I4 and I5. In this manner ice formations are broken by the flexing of the side regions 25 and 26 of the tube and the stretching of the portions I4 and I5 reducing the adhesion of the ice thereto and facilitating ice removal by the ambient airflow.

While the sides of the tube portion are moving and bulging outwardly during inflation, the intermediate region 21 of the outer wall 23 immediately at the leading edge I2 is distended attaining a relatively highly stretched condition 45 together with maximum change of curvature by virtue of the elasticity of the rubber-like material thereof, which action effectively diminishes the adhesion of the ic'e cap to the outer surface layer and fractures the ice cap immediately at the 50 leading edge thereby unbalancing and moving laterally the broken ice relative to the airflow for removal by the ambient airstream. The cooperation of the tube portion I3 and the stretchable portions I4 and I5 thus provide effectively 55 for the removal of ice accumulation on airfoilsy having thin-section leading edges despite the tendency of the ice under such conditions to resist dislodgment.

Variations may be made without departing 50 from the scope of the invention as it is dened in the following claims.

I claim:

1. An inflatable shoe for preventing the accumulation of ice on an airfoil having a thin-section leading edge, said shoe comprising a tube portion of elastic material extending longitudinally of the shoe and stretchable portions of elastic material at the sides of said tube portion extending toward the margins of the shoe, said 70 tube portion having an inner and an outer wall adaptedto be distended upon inflation of the tube portion and said tube portion including a stretch-resisting fabric element in said inner Wall said outer wall for resisting stretch of said inner wall and said side regions, said element having margins spaced apart in said outer Wall leaving an intermediate region of said outer wall of relatively high stretchability.

2. An inflatable shoe for preventing the accumulation of ice on the leading edge of an airfoil, said shoe comprising a covering for disposition across the leading edge and to a rearward region of said leading edge, said covering comprising an inflatable chamber having a forward wall distensible forwardly under inflation of said chamber and said covering comprising an attaching portion extending rearwardly from said forward wall, said attaching portion including a stretchable portion resiliently restraining the forward distention of said forward wall, and means comprising stretch-resisting material united with said covering and wholly disposed intermediate said forward wall and said stretchable portion for locally restraining outward distention of the covering in the region of saidstretch-resisting material while permitting the forward distention of said forward wall.

3. An inflatable shoe for preventing the accumulation of ice on the leading edge of an airfoil, said shoe comprising a covering for disposition across the leading edge and to a rearward region of said leading edge, said covering comprising an inflatable tube having a forward wall joining the back wall of the tube in the rear margin of the tube, said forward wall being distensible forwardly under inflation of the tube, and said covering comprising an attaching portion extending rearwardly from said forward Wall at said rear margin of the tube, said attaching portion including a stretchable portion resiliently restraining the forward distention of said forward wall, and means comprising stretch-resisting material united with said covering and disposedat said rear marginof the tube and wholly located intermediate said forward wall and said stretchable portion for locally restraining outward distention of the covering in the region of said stretchresisting material while permitting the forward distention of said forward wall.

4. An inflatable shoe for preventing the accumulation of ice on the leading edge of an airfoil, said shoe comprising a covering for disposition across the leading edge and to rearward regions of said leading edge, said covering comprising an inflatable tube having a forward wall joining' the back wall of the tube in rear margins of the tube, said forward wall being distensible forwardly under inflation of the tube, and said covering comprising attaching portions extending rearwardly from said forward wall at said rear margins of the tube, said attaching portions inc1uding stretchable portions resiliently restraining the forward distention of said forward wall, and means comprising stretch-resisting material united with said covering and disposed at said rear margins of the tube and wholly located intermediate said forward wall and said stretchable portions for locally restraining outward distention of the covering in the region of said `stretch-resisting material while permitting the forward distention of said forward wall.

5. An inflatable shoe for preventing the accumulation of ice on the leading edge of an' airfoiL. saidshoe comprising a covering for disposition across the leading edge and to a rearward region of said leading edge, said covering comprising an inflatable tube having a forward wall joining the and in longitudinally extending side regions of back'wall of the tube in a rear margin of the tube, said forward wall having a front portion distensible forwardly under inflation of the tube, and said covering comprising an attaching portion extending rearwardly from said forward wall at said rear margin of the tube, said attaching portionincluding a stretchable portion resiliently restraining the forward distention of said front portion, and stretch-resisting material united with said covering at said back wall of the tube and extending into said rear margin and terminating to provide said front portion of said forward wall devoid of said material and for locally restraining outward distention of the covering in the region of said stretch-resisting material while permitting the forward distention of said front portion.

6. An iniiatable shoe for preventing the accumulation of ice on the leading edge of an arfoil, said shoe comprising a covering for'disposition acrosstlie leading edge and to rearward regions of said leading edge, said covering comprising an inflatable tube having a forward wall joining the back wall of the tube in rear margins of the tube, said forward wall having a -front portion distensible forwardly under inflation of the tube, and said covering comprising attaching portions extending rearwardly from said forward wall at said rear margins of the tube, said attaching portions including stretchable portions resiliently restraining the forward distention of said front portion, and stretch-resisting material united with said covering at said back wall of the tube and extending into said rear margins and terminating to provide said front portion of said forward wall devoid of said material and for locally restraining outward distention of the covering in the region of said stretch-resisting material while permitting the forward distention of' said front portion.

7. An inflatable shoe for preventing the accumulation of ice on the leading edge of an airfoil, Said shoe comprising a covering of rubber-like material for disposition across the leading edge and to rearward regions of said leading edge, said covering comprising an inflatable tube having a forward wall joining the back wall of the tube in rear margins of the tube, said forward wall having a front portion distensible forwardly under ination of the tube, and said covering comprising attaching portions extending rearwardly from said forward wall at said rear margins of the tube, said attaching portions including stretchable portions resiiiently restraining the forward distention of said wall, and stretchresisting sheet fabric reinforcement embedded in said rubber-like material at said back wall of the tube and extending into said rear margins and terminating to provide said front portion of said forward wall devoid of said reinforcement and for locally restraining the outward distention of the covering in the region of said reinforcement while permitting the forward distention of said front portion.

WILLSON H. HUNTER.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 2,306,759 Sears Dec. 29, 1942 1,998,809 Geer Apr. 23, 1935 

